In principle, Fiberglass Pools may seem to be the easiest type of pool to install. Just dig a hole and drop it in…right? In theory that’s correct, but it’s not quite that simple. In fact, installers make mistakes all the time, and a poorly installed pool makes for an unhappy pool customer. So if you are considering the purchase of a fiberglass pool you’re in luck. We’re about to discuss the 5 Keys to a successful fiberglass pool installation. Let’s jump right in!
Key #1: A Solid Foundation
This may seem like a no-brainer but it is the culprit behind the failure of many pool installations. Here are a couple things to watch out for:
o Setting the pool shell on disturbed soil- When the hole is being dug, if the excavator accidentally digs too deep there is a tendency to build that area back up with the same soil. That’s a big no no! The area must be brought up to grade with a compactable base material. If this is not done correctly, the ground will eventually settle and so will the pool. It doesn’t take a brain surgeon to know that means trouble.
o Uncompacted base material- After the hole is excavated a leveling material such as sand or gravel is dumped in the hole and is leveled as a base for the pool shell to rest on. If this material is not properly compacted the pool will settle over time.
These problems can be easily avoided by the contractor by taking the necessary time to insure the pool rests on a solid foundation. We have written extensively on this topic and are proponents of clean crushed gravel as a base material.
Key #2: Sound Pool Leveling Methods
Because a fiberglass pool is a one piece unit it is not realistic to expect that it will be perfectly level. The industry standard states that the pool can be up to one inch out of level in forty feet. We shoot to get the pool within a quarter but will settle for a half-inch. I have seen installers will use any means under the sun to get the pool shell level and some methods are perfectly fine, and others are frankly kind of scary.
We teach that the best method to level a fiberglass pool is to completely lift the pool out of the hole and either add or take away material to get the pool to the desired level. We also teach to walk the pool floor after the shell is set to insure the entire pool is resting on base material without voids. These two techniques will insure that the pool is not only level, but resting in its natural state and free of disproportionate stress at any point.
Key # 3: Sound Plumbing
What we’re really talking about here is the “L” word: leaks! Yes it is a dirty word, especially in the pool business. There are 3 things an installer should do to protect against leaks:
o Secure the plumbing- Because fiberglass pools have a tremendous amount of backfill material that can settle over time, it’s necessary to secure the plumbing to insure that it doesn’t move. Plumbing settlement results in leaky fittings in the pool and is a major pain to repair. We tie our plumbing up with cable to protect against any settlement.
o Use rigid PVC pipe- There are two predominant types of PVC used around inground pools, flex pipe and rigid pipe. Flexible PVC, as its name implies, will easily contour with the shape of the pool and make for a quicker installation. The problem with flex pipe is that it is not suitable for underground use according to the manufacturers of the product. They state this because the material is susceptible to damage from termites. We have also found that the pipe is prone to collapse under pressure and that the glue joints do not hold as well. Rigid pipe on the other hand, is much more durable and can also be contoured to follow the pool shell by a process called heat bending that we teach via video. This gives you all of the flexible advantages of flex pipe with the durability of rigid pipe. You simply have to be willing to invest the time to get it done.
o Pressure Testing- This should never be neglected. It’s better to find a leak now than later, especially if later is after the concrete patio is poured! This is pool install 101, but there are many contractors who still don’t pressure test their plumbing.
Key #4: Good Backfill Procedure
Backfilling the pool shell is a process that can have serious consequences if done improperly. Here are some backfilling guidelines:
o Bring the backfill material up on the outside of the pool with the water level on the inside of the pool. This keeps relatively equal pressure on the walls of the pool.
o Compact the backfill material to insure minimal settlement. Sand backfill requires saturation with water every six to twelve inches of lift. Clean gravel backfill compacts on placement and requires no additional compaction methods.
o Pack the steps and seats with backfill material to eliminate voids as much as possible. This is done by literally crawling under the pool and stuffing backfill material into the area with a board or other tool. It’s important to make sure there is at least a foot of water in the pool before beginning this process so the entire pool is not lifted from the ground.
o Brace large steps and benches with block to protect against sagging.
If backfilling is done improperly excessive settlement, bulged and crooked walls, or sagging steps and benches are some of the consequences. We are also huge proponents of clean crushed gravel as a backfill material.
Key #5: Quality Cantilevered Coping
A perfect pool installation can all be for naught if the coping of the pool is of poor quality. In many respects the coping can either make or break the entire job. Cantilevered concrete coping is poured in place on top of the pool and is a skill that requires significant experience to master. The two primary steps to producing successful cantilevered concrete are:
1. Proper form installation- Because the forms must contour with the pool, Styrofoam is the material of choice. The forms must be installed so they are secure enough to withstand the pressures exerted by the concrete and true enough to maintain their desired shape.
2. Proper concrete placement- As the concrete is placed against the form it is necessary to remove air pockets by tapping vigorously against the outside of the form.
A good cantilevered coping job will be free of significant air pockets and exposed gravel and the surface will be uniform and relatively smooth.
Well there’s some food for thought for those of you considering the purchase of a fiberglass pool. Based on my experience it would be wise to devote as much energy to finding the right pool contractor as the right pool manufacturer.